Process for amalgamating metals



R. H. STEVENS.

PROCESS FOR AMALGAMATING METALS. APPLICATICN} FILED AUG.29, 191s.

\ 1,384,683, Patented July 12,1921.

jvmem or" P67750771 fi 5%6516/25 His 2 UNITED STATES PATENT OFFICE.

RANSOM H. STEVENS, OF LOS ANGELES, CALIFORNIA, ASSIGNOR OF ONE-THIRD TO W. R. CROWELL AND ONE-THIRD TO L. C. COMER, BOTH OF LOS ANGELES, CALI- FORNIA.

PROCESS FOR AMALGAMATING METALS.

To all whom it may concern Be it known that I, RANsoM H. STEVENS, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles, State of California, have invented new and useful Improvements in Processes for Arnal gamating- Metals, of which the following is a specification.

This invention relates to processes for amalgamating metals; and although the process is generally intended and adapted to all kinds of amalgamation worl that is the gathering of metallic particles into the body of a liquid metal masscoalescing the metallic particles with that mass-the process is particularly designed for the eflicient recovery of gold that has been .fioured with mercury and is recoverable only with difiiculty by other methods.

The process has fundamentally to do with the passing of a current or stream of pulp liquid through an amalgamating metal or metals (such; as mercury, etc.,) under the action of an electric current, in such a way that the stream of pulp liquid and suspended amalgamable metals passes through an electric current immediately before or at the time of entering the amalgamating metal. The process may be effectively carried on in an apparatus wherein the pulp liquid stream passesunder the lower edge of a wall which dips into the metal bath, such as a mercury bath. Electrodes are provided to apply an appropriate current to the flowing pulp liquid; and the amount of current is regulated in accordance with the charac, ter and amount of metal to the recovered, the speed of the pulp liquid stream, and. generally in accordance with the size and capacity of the apparatus. The process will be best understood when it is explained in connection with a suitable form of appara-. tus; such apparatus being illustrated in the accompanying drawings where Figure 1 is a vertical section and perspective of the apparatus; and Fig. 2 is an enlarged diagram illustrating the action. r

. In the drawings I-show a box having a back wall 10, side walls 11' and a front overflow wall 12. A partition wall 13 forms with theback and sidewalls a chamber'in which pulp liquid 14 is maintained at any suitable level The'fluid stands at level L in the chamber in front of partition wall Specification of Letters Patent.

Application filed August 29, 1918. Serial No. 251,909.

13, level L being determined by the height of over-flow wall 12. The height of level L above level L is governed in accordance with the amount of flow desired under the lower edge 13" of partition wall 13. With any given apparatus the rate of flow depends entirely upon the heightof level L,

Lower edge 13 of partition wall 13 dips into a mercury or other amalgam ating metal bath shown at 15, contained in a metal pan 16 having an electric connection means at 17. This metal bath may extend its metallic surface somewhat to each side of the wall 13, so that aconsiderable metallic surface may be exposed and so that a considerable mass of metal may be placed in the amalgamat ing bath without having anexcessive distance between the lower edge 13 and the bottom of pan 16. It is an object to have this distance comparatively small so that the stream of pulp liquid is spread out into thin stream in passing under the wall 13; so that all parts of the metal. carrying pulp liquid are intimately exposed to the amalgamating action of the metal in the bath. The eflicient dimension for this height of opening having been determined, the capacity of the apparatus may be increased by increasing the length of the passage space under wall edge 13; that is, by increasing the dimension of the apparatus in a direction at right angles to the surface of the drawing. Thus in practice the opening below the edge 13 may become a long, narrow opening.

On the opposite sides of partition wall 13, above its lower edge, are two electrode plates 20, whichmay preferably be of carbon or any other suitable conducting material. Connections 21 extend from these electrode plates to an electrical connection at 22. The electrode plates extend the whole length of partition wall 13 and the lower edges of the electrode plates are at a suitable distance above the level of the liquid bath 15. 1 Positive electrical connection is made at 22 and negative electrical connection is made at 17 so that current flows downwardly from the two electrode plates 20 to the surface of metal 15, through the pulp liquid; and the metal carried in suspension in the fluid will thus be subjected to the electrical action just as it enters and just as it leaves the amalgamating liquid. The metal is amalgamated into the amalgamating liquid and remains the bath 15, whilo the spent pulp liquid passes into the frontchamber and overflows the wall 12.,

In operating this apparatus, and carrying on my process, I first prepare the ore by forming a thin pulp liquid with water; and

i this fluid, with its suspended ore and metalthe amalgamating metal. It will be noted that the pulp liquidis spread out into a comparatively thin stream also where is passes the electrodes; the distance between the electrodes and the amalgamating metal being gaged to obtain maximum electrical effect on the pulp liquid as it passes through the space denoted 25. The current flow is most concentrated directly down onto the mercury, but it may also flow somewhat diagonally outwardly to the outer'parts of the'mercury bath and also to the exposed edge portions of the pan 16. The head or liquid in the rear column at 14 causes the mercury surface to beLdisplaced downwardly on the rear side of the wall 13; so that the pulp liquid may flow under the wall. This displacement, when the pulp liquid stream is flowing, may be more or less exclusively near and under the wall 13; so that the situation will. be more or less like that'illustrated in Fig. 2. However, in the displacement space near and under the wall 13, the pulp liquid is at all times in intimate contact with the amalgamating liquid. Consequently, it will be seen, the pulp is subjected to electrical action simultaneously with its V subjection to intimate relation to the mercury. The electrical current notonly flows through the stream" to the body of mercury beneath but flows through a stream of pulp liquid that is more or less intermingled with and in intimate contact withv the mercury. Substantially all of the metal is caught and held in the amalgamating bath. This is particularly true, and the process is'par- V ticula-rly efficacious, as applied to oreslco'n-l taining gold that has been floured with mercury. Under the action of theelectri'cal current and theamalgamating action of the mercury bath, the floured gold is readily amalgamated and coalesced into the body of mercury, leaving the spent 'o'r'e' in suspended form to overflow wall. 12. Under different conditions. the amount of voltage and am- 'perageof the electric current will be difie'r ent; depending upon the amount and char acter of ore and the speed at which it is put through the apparatus. In atypical small sized apparatus'where the passage under the lower edge 13 of the partition wall is from one-half to three-quarters of an inch in height, where the wall 13 dips one-eighth-to one-quarter of. an inch into the mercury, and

where the electrodes are one-quarterto onehalf an inch abovc the mercury, using mercury in the bath 15 and operating upon flouredgold ore, a voltage of from ten; to twenty volts may be sufficient; the amperage will depend upon the conductivity of the strated the practicability andefiectiveness" of the invention. a p

The eltect of passing the electric current through the pulp liquid prior to'the latter coming into contact with the mercury seems to carrythe metal particles toward the mercury and this action is found to be more effective in that portion ofthe flow of pulp liquid which is toward the mercury .than in the portion flowing away therefrom] That is, such effect is greater at the left hand side of the partition in Fig; 1 than at the right thereof. 1 The combined physical movementof the pulpliquid toward the mercury and the movement of the electric current through the pulp liquid toward the mercury causes the metal particles to be carried into direct and intimate contact with the mercury.

' Having described'my invention, I claim 1; The processof amalgamating metals the metal to be amalgamated beneath a p'artition that extends below the level of a body of an amalgamating substance, the upper surface of the'amalgamating substance being depressed beneath the artition by the weight of the body of liquid to format passage through which the liquid flows in contact with the amalgamati'ng' material, and causing an electric current to. flow through the liquid prior to' andwhile it isin condition with the amalgamating substance. 'l

'whichembodies passing-a liquidcontaining '2. The process of amalgamating metals which'embodies passing a "liquid containing the metal to be amalgamated beneath a partition that extends below the l'evel of a body of an amalgamating substance'supported by a receptacle constituting a portion of an elec tric circuit,theupper surface of the amalgamating' substance being depressed beneath the partition by the weight'ofthe body of :liquid to form a passage through which the liquid flows in contact withthe amalgamating material, and causing an electric current to pass through the liquid to's'aid receptacle both above the levelof the amalgamating substance therein andthrough said substance. 3. The process. of amalgamatingfmetals which embodies passing a liquidc'ontaining the'metal to be amalgamated beneath a partition that extends below the level of a body of an amalgamating substance supported by .a receptacle constituting a portion of an electric circuit, the upper surface of the amalgamating substance being depressed beneath the partition by the Weight of the body of liquid to form a passage through which the liquid flows in contact With the amalgamating material, and causing an electric current to pass from opposite sides of the partihave hereunto subscribed my name this 24.- 15

day of August, 1918.

RANSOM I-I. STEVENS.

Witness VIRGINIA I. BERINGER.. 

